Background/objectives: Pancreatic ductal adenocarcinoma (PDAC) incidence is rising, and prognosis remains poor due to late diagnosis and limited effective therapies. Currently, patients are treated based on TNM staging, without molecular tumor characterization. This study aimed to validate a technique that combines the amplification refractory mutation system (ARMS) with high-resolution melting analysis (HRMA) for detecting mutations in codon 12 of KRAS in tumor and plasma, and to assess its prognostic value.
Methods: Prospective study including patients with newly diagnosed PDAC with tumor and plasma samples collected before treatment. Mutations in codon 12 of KRAS (G12D, G12V, G12C, and G12R) were detected using ARMS-HRMA and compared to Sanger sequencing (SS). Univariate and multivariate analyses were used to evaluate the prognostic significance of these mutations.
Results: A total of 88 patients, 93% with ECOG-PS 0-1, 57% with resectable disease. ARMS-HRMA technique showed a higher sensitivity than SS, both in tumor and plasma (77% vs. 51%; 25 vs. 0%, respectively). The most frequent mutation was G12D (n = 32, 36%), followed by G12V (n = 22, 25%). On multivariate analysis, patients with G12D and/or G12C mutations, either in tumor or plasma, had lower PFS (HR 1.792, 95% CI 1.061-3.028, p = 0.029; HR 2.081, 95% CI 1.014-4.272, p = 0.046, respectively) and lower OS (HR 1.757, 95% CI 1.013-3.049, p = 0.045; HR 2.229, 95% CI 1.082-4.594, p = 0.030, respectively).
Conclusions: ARMS-HRMA is a rapid and cost-effective method for detecting KRAS mutations in PDAC patients, offering the potential for stratifying prognosis and guiding treatment decisions. The presence of G12D and G12C mutations in both tumor and plasma is associated with a poorer prognosis.
Keywords: ARMS–HRMA; KRAS mutations; amplification refractory mutation system; ctDNA; liquid biopsy; pancreatic cancer; prognosis.